Communication failure in DSL circuits typically results from noise or other problems in the DSL circuit. Correction of the failure and improvement of the DSL service typically involves measurement, identification, and isolation of noise in a wide frequency range, for example in a range of 4000 Hz up to 30 MHz.
Currently available wideband DSTL measurement methods are low impedance, highly invasive and require disruption of the communications link between the telephone company DSL terminal (DSLAM) and the subscriber home DSL equipment. These methods require connection at either end of the DSL communications line, thereby preventing DSL communications and disturbing the measurement environment.
One example of such a measurement tool is multifunction test tool sold by Tempo under the trademark Sidekick® Plus. A typical cable used to carry telecommunication signals from the DSLAM to the subscriber's home DSL equipment includes a plurality of twisted pairs surrounded by a cable shield and a sheath. The test tool provides for connection of the test tool to the twisted pair to carry out a plurality of tests which assist in measuring, identifying and isolating noise and other problems on the twisted pair. The Sidekick® Plus, for example, is capable of performing loop current tests, longitudinal balance (Stress Test), transmission and noise tests. As with other currently available test tools, the Sidekick® Plus is low impedance, highly invasive and requires disruption of the communications link between the DSLAM and the subscriber's home DSL equipment. The disruption of the communication link not only prevents DSL communications but disturbs the measuring environment.